1. Technical Field
This invention pertains to a method and tool for cutting, suitable for cutting such diverse materials as tree branches, carpet and flooring materials, wire, construction materials, automotive moldings and trim, wood trim, rope, vinyl, hose, rubber, plastic, thick paper, and leather.
2. Background Art
A number of different utility tools are commercially available for a variety of cutting jobs. Some commonly used cutting tools rely on coordinating blades which are moved adjacent to each other to cut materials placed between the blades. Examples of shears using this method of cutting are found in U.S. Pat. No. 5,469,625 to Melter et al. and U.S. Pat. No. 5,511,314 to Huang. Huang utilizes the dual blades by leaving one blade in an indentation of the material being cut created by a first effort of cutting, as the coordinating blade is released and then closed again to effectively whittle away a branch or other material to be cut. Both Huang and Melter teach the use of a connecting link to achieve a mechanical advantage as the handles of the shears are forced together, increasing the force applied to the cutting blades as they are closed around the material to be cut. While this mechanical advantage allows branches and other materials to be efficiently cut, the life of such tools is limited. With use, the blades are eventually bent away from each other as the force of cutting pushes the blades outward from each other, wearing on the fulcrum or pivot points by which the jaws of the shears are connected to each other.
Similarly, U.S. Pat. No. 5,566,453 to Lin describes a pair of gardening shears that include a connecting link to provide a mechanical advantage for increasing the force applied to a workpiece being cut. Lin does not use opposing and adjacent blades, but rather drives a blade into a serrated curved fang. As with the previously mentioned shears, use of the Lin shears will eventually strain the pivot points at which the adjacent handles are attached to each other, possibly resulting in misalignment of the shears.
Other common cutting tools utilize a single blade which closes onto an anvil, cutting materials placed between the open blade and the anvil as the blade closes. Examples are found in U.S. Pat. Nos. 5,272,810 to Orthey and 5,003,695 to Lipscomb et al. Orthey discloses garden shears having an anvil and opposing blade connected to handles which are connected at a pivot point. Addressing the problem that use of the shears eventually results in misalignment of the blade and anvil, Orthey provides a mechanism for adjusting the anvil with respect to the blade, to correct such misalignment and extend the useful life of the tool. Lipscomb teaches snips with a rotatable anvil and two handles attached side-by-side at a pivot point.
A blade and anvil cutting tool is sold by Craftsman tools under the tradename "Handi-Cut". The Craftsman product is labeled to provide notice that a patent application is pending. The Craftsman tool has two jaws, with a reduced diameter segment of one jaw fitting within a channel of the other jaw. In this manner, the jaw supporting the blade can be moved around a pivot point, as that blade jaw is moved toward the anvil supported by the other jaw. The Craftsman product does not enjoy the mechanical advantage of a connecting link to leverage force applied to one handle, and the channel through which the reduced diameter segment fits is not suitable for receiving such a mechanism.
While each of these cutting tools is useful for its intended purpose, none provides a significant mechanical advantage to leverage the force applied on tool handles while also avoiding the misalignment and decreased efficiency caused by long-term stress to fulcrum points which hold together adjacent jaws.